SPSS® 12.0 Command Syntax Reference

472 DISCRIMINANT
Example
DISCRIMINANT GROUPS=SUCCESS(0,1)
/VARIABLES=V10 TO V15, AGE, V5
/ANALYSIS=V15 TO V5
/ANALYSIS=ALL.
• The first analysis will use the variables V15, AGE, and V5 to discriminate between cases
where SUCCESS equals 0 and SUCCESS equals 1.
• The second analysis will use all variables named on the VARIABLES subcommand.
Inclusion Levels
When you specify a stepwise method on the METHOD subcommand (any method other than
the default direct-entry method), you can control the order in which variables are considered
for entry or removal by specifying inclusion levels on the ANALYSIS subcommand. By
default, all variables in the analysis are entered according to the criterion requested on the
METHOD subcommand.
• An inclusion level is an integer between 0 and 99, specified in parentheses after a variable
or list of variables on the ANALYSIS subcommand.
• The default inclusion level is 1.
• Variables with higher inclusion levels are considered for entry before variables with lower
inclusion levels.
• Variables with even inclusion levels are entered as a group.
• Variables with odd inclusion levels are entered individually, according to the stepwise
method specified on the METHOD subcommand.
• Only variables with an inclusion level of 1 are considered for removal. To make a variable
with a higher inclusion level eligible for removal, name it twice on the ANALYSIS
subcommand, first specifying the desired inclusion level and then an inclusion level of 1.
• Variables with an inclusion level of 0 are never entered. However, the statistical criterion
for entry is computed and displayed.
• Variables that fail the tolerance criterion are not entered regardless of their inclusion level.
The following are some common methods of entering variables and the inclusion levels that
could be used to achieve them. These examples assume that one of the stepwise methods is
specified on the METHOD subcommand (otherwise, inclusion levels have no effect).
Direct. ANALYSIS=ALL(2) forces all variables into the equation. (This is the default and can be
requested with METHOD=DIRECT or simply by omitting the METHOD subcommand.)
Stepwise. ANALYSIS=ALL(1) yields a stepwise solution in which variables are entered and
removed in stepwise fashion. (This is the default when anything other than DIRECT is specified
on the METHOD subcommand.)
Forward. ANALYSIS=ALL(3) enters variables into the equation stepwise but does not remove
variables.
Backward. ANALYSIS=ALL(2) ALL(1) forces all variables into the equation and then allows
them to be removed stepwise if they satisfy the criterion for removal.